Is LED lighting for reef tanks too blue? Is Broader spectrum better? Only time will tell.

I know I can post these sorts of things on a larger forum but I'm finding that the larger forums tend to be dominated by folks with strong opinions. Personally, I'm happy with just points of view based on anecdotal evidence that the rest of us can emulate. This said...here's a very popular comment over the years that has great anecdotal evidence to back it up, "6500K grows SPS fastest but 10K or more has better color."  I tend to agree with this comment as some of the best SPS dominant tanks were using 6500k MH with supplemental actinic fluorescent. So why are most LED driven reef tanks so blue? I think it's a mistake.   

I'm running 100% LED lighting and it is blue dominant for certain. I have all kinds of SPS in there and with exception to the recent death of a montipora setosa, I haven't had one single casualty. However, I've had much better results with tradtional MH and T5s.  Here's a short list of coral with my subjective opinion on how they are doing in groups of species

Acropora: 
All my acros, with the exception of my ora red planet, are doing very well. Great growth and coloration. The only coral in my tank doing better are my Zoas, Porites, and Stylophora.  

Millepora: doing almost as well as the acros as far as growth...just lacking some color. My Halloween Millepora is a bit brown but growing very fast. 

Montipora: my Monti's aren't doing that great overall. My monti caps (red and purple) are growing OK but not as fast as they should and color is a bit dull. I lost my setosa and nearly lost my digitata until I moved it to a lower spot in the tank with better flow. Strangely enough, I have spiderman (or is it superman?) montipora that has been encrusting along great and holding it's color. 

Porites: I have a green Porite that is doing fantastic. It has great color and growth and always happy with fully extended. Recently it has been turning from an interesting lime green to more eye-catching yellow-green. It's now one of the nicest corals in my tank. 

Stylophora: I have two different species at the top of the tank that are growing so fast that they've nearly doubled in size in 4 months. At the rate they are growing, I will have to aggressively prune them back and frag them out. They are always happy with excellent polyp extension. I'll be adding a purple stylo soon. 

Zoas: I have a few different kinds of Zoas...all stowaways on my live rock. My Zoas are spreading fast and the color is outstanding. In fact, they're pretty much the first thing people notice in my tanks other than my green star weeds...I mean polyps. 

On this topic of weeds...I have a few softies that are growing like mad such as nuclear green candy cane and two types of Xenia. I'm getting rid of all my softies as soon as my buddy get's his tank cycled and online. I'm tired of fragging them out to keep them under control. 

Now for my theory: 
I personally believe that LEDS used for reef tanks are too blue, which is the cause of the bleaching and browning out that many people are seeing. My guess is that other spectrums may play an unforeseen role in overall coral health. I think we need to step back and consider that the idea should be to replicate what we know already works. For example, the best reef tanks that I've seen over the years are 6500K Metal Halide with supplemental actinic (420 nm) such as using fluorescent T5s. So, my plan is to remove half of my cool whites and replace them with warm and neutral white with high CRI index so I know they are full spectrum. I'm also going to replace a few blues with 405-430 nm violet LEDs. The idea here have more of a natural daylight look but have the colors really pop with actinics.  

I'll try to keep a photo log of this when I finally get around to it. But with running a day job, two startups, a newborn...and two toddlers...my time is limited.

Wow that was a read up haha, basically as I see it you can not directly associate growth with the type of lights you run. I associate myself with hobbiests that run every type of lighting that you could possibly run. I run t5s and have amazing growth and can pretty much keep every type of coral happy as long as my tank chemistry is balanced. But I have seen tanks with LEDs have amazing growth in the end as long as you have enough light where your coral can photosynthesise over the amount of time they need, the growth rate should mainly have to so with chemistry, flow, and temperature fluctuations. IME if the coral has sufficient light it can grow quickly of provided and enviornment that is a close copy of our ocean. This is just my experience and I mean I copy those who have the greatest success.

Personally, I believe your theory is correct but I don't believe your reasoning is.

Bleaching under 'blue' shifted LED lit tanks IMO is due to 1 thing, too much intensity in 1 small spectral range that corresponds with a photosynthetic peak.

A lot of people like the blue look because that is how corals look in nature due to saltwater filtering out the higher spectrums before they reach the corals.

Problem with that when dealing with LEDs is most people use heavy amounts of royal blue. Too much will cause photo saturation and inhibition quickly in corals. They don't look that intense to the eye, but they are, and they are very damaging to the eye if you look directly at them (google blue light harmful to eyes).  

A frag tank can be lit with just blue light, and very few, to where PAR never exceeds 100, and I have yet to see a coral that won't flourish under 20-100 PAR of just blue light. Cool whites also contain a lot of royal blue spectrum. When you combine cool whites with royal blues and push the intensity to the point it matches something like a 250w MH (to your eyes), most of the time the corals will die due to too much blue in the spectrum. If you stretch out the blue spectrum, utilizing the entire 400nm range instead of focusing on 455nm, you can still achieve the blue preference without killing corals.

JMO